WO2015173934A1

WO2015173934A1 - Method and device for separating and recovering supercritical fluid

Info

Publication number: WO2015173934A1
Application number: PCT/JP2014/062997
Authority: WO
Inventors: 齋藤　崇; 清隆上野
Original assignee: Ykk株式会社; 株式会社日阪製作所
Priority date: 2014-05-15
Filing date: 2014-05-15
Publication date: 2015-11-19
Also published as: TW201603883A; CN106457103A; TWI566833B

Abstract

　Provided is a method for separating and recovering a supercritical fluid, the method making it possible to reduce maintenance frequency while maintaining a high separation and recovery efficiency. A method for separating and recovering a supercritical fluid including a step 1 for readying a supercritical fluid containing an impurity, a step 2 for changing the fluid into a gaseous state, a step 3 for separating the liquid-state impurity from gaseous-state fluid using a non-adsorption filter (205) having a first mesh size, and a step 4 for using an adsorption filter (216) for further separating the liquid-state impurity from gaseous-state fluid after step 3 using an adsorption filter (216).

Description

Method and apparatus for separation and recovery of supercritical fluid

The present invention relates to a supercritical fluid separation and recovery method and apparatus. In particular, the present invention relates to a method and apparatus for separating and recovering a supercritical fluid used in a supercritical staining apparatus.

Conventionally, when dyeing textile products, a large amount of water has been used as a dyeing medium, but problems such as saving water resources and wastewater treatment have been pointed out, and dyeing technology with a lower environmental impact has been pointed out. Development was required. Therefore, in recent years, a method using a supercritical fluid typified by supercritical carbon dioxide as a dyeing medium has been proposed as a dyeing method in which the amount of waste liquid discharged is extremely small as compared with the prior art. The supercritical fluid after the dyeing process is reused after separation of impurities such as dyes and a predetermined process.

Japanese Patent No. 3954103 (Patent Document 1) discloses a dyeing apparatus and a dyeing method for dyeing a textile product using a supercritical fluid. As shown in FIG. 5, the dyeing apparatus 70 described in Patent Document 1 includes an autoclave 71 that stores a textile product, a storage tank (liquid reservoir) 72 that stores a fluid that is a dyeing medium, and a storage tank 72. From the pump 73 for supplying the fluid to the autoclave 71 and increasing the pressure of the fluid, the heat exchanger 74 for heating the fluid to be in a supercritical state, and a supercritical state. Dissolving tank (saturator) 75 for dissolving the dye in the fluid (supercritical fluid), a pressure release valve 76 for adjusting the pressure in the autoclave 71, and a separation for separating the dye from the fluid, arranged downstream of the pressure release valve 76 It has the tank 77 and the condenser 78 which condenses the fluid which the dye isolate | separated.

The supercritical fluid that has passed through the autoclave 71 is transported to the pressure release valve 76 side and / or to the pump 73 side by controlling the opening and closing of the

valves

92 and 93 disposed on the downstream side of the autoclave 71. In this case, the supercritical fluid transported to the pressure release valve 76 side is reduced in pressure by being discharged from the pressure release valve 76 and vaporized, and then the dye is separated from the vaporized fluid by precipitation in the separation tank 77 and collected. It is done. Further, the fluid from which the dye is separated in the separation tank 77 is returned to the storage tank 72 after being liquefied by the condenser 78.

In JP 2004-249175 (Patent Document 2), after impregnating a base material with an impregnating substance in supercritical carbon dioxide in an impregnation treatment tank, a pressure reducing valve is inserted into the fluid after the impregnation treatment from the impregnation treatment tank. The gas separation device is used to remove liquid or solid components, and the obtained carbon dioxide gas is compressed into liquefied carbon dioxide or supercritical carbon dioxide and then stored in a storage tank. The liquefied carbon dioxide or supercritical carbon dioxide derived from the above is heated or compressed as necessary and then supplied into the impregnation tank, and the impregnation tank is filled with supercritical carbon dioxide. Carbon dioxide is recovered and reused. A processing method is described.

In Patent Document 2, it is said that by providing a filter in the gas separation device, the separation efficiency is improved when a liquid or solid component is removed by the gas separation device. Nonwoven fabrics and woven fabrics are described as filter materials. In order to improve gas separation efficiency, it is also described that it is preferable to arrange a filter having pleats in a cylindrical shape and to pass carbon dioxide gas from the outside toward the inside.

In Japanese Patent No. 4669231 (Patent Document 3), waste materials are continuously separated from carbon dioxide discharged from a cleaning device or a drying device using supercritical or liquid carbon dioxide, and the recovered exhaust fluid dioxide is recovered. For the purpose of providing a carbon dioxide regeneration and recovery device capable of reducing the residual components in carbon to a predetermined value, the temperature and pressure adjustment of the discharged fluid is controlled so as to maintain a predetermined gas-liquid ratio. There has been proposed a gas-liquid separation mechanism comprising a temperature adjustment means and a pressure adjustment means, and a gas-liquid separation pressure vessel for separating the discharged fluid pressure-adjusted by the temperature adjustment means and the pressure adjustment means into a gas and a liquid.

Gaseous carbon dioxide obtained by the gas-liquid separation mechanism is introduced into the mist separation mechanism, and the mist is separated. Further, the unwanted matter in the carbon dioxide from which the mist has been separated is removed by the unwanted matter removing mechanism. Both the mist separation mechanism and the unwanted matter removal mechanism are provided with a filter. The mist separation mechanism captures liquid, and the unwanted matter removal mechanism fixes the unwanted matter to the adsorbent.

Japanese Patent No. 3954103 JP 2004-249175 A Japanese Patent No. 4669231

Thus, in the prior art document, there is a description of a method for separating and recovering a supercritical fluid. However, Patent Document 1 discloses that the dye is separated and collected from the vaporized fluid by precipitation, but the specific mechanism is not clear. Patent Document 2 describes that a filter is provided in the gas separation device. However, the mechanism described in the document requires frequent replacement of the filter, so that practicality is insufficient. is there. Further, Patent Document 2 only discloses a gas separation mechanism using a filter. If the mechanism is composed of only a filter, it is difficult to separate unnecessary substances, particularly mist components. In Patent Document 3, since the exhaust fluid enters the gas-liquid separation pressure vessel at a predetermined gas-liquid ratio, the liquid-state exhaust fluid and the gas-state exhaust fluid coexist in the gas-liquid separation pressure vessel. For this reason, it is difficult to remove impurities dissolved in the liquid, and high pressure resistance is required to hold the discharged fluid in a liquid state in the gas-liquid separation pressure vessel.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a supercritical fluid separation / recovery method or separation / recovery device capable of reducing the maintenance frequency while maintaining high separation / recovery efficiency.

In one aspect of the present invention,
Preparing a supercritical fluid containing impurities;
Step 2 of changing the fluid to a gaseous state;
Using a non-adsorbing filter having a first opening to separate impurities in a liquid state, a solid state or a mixed state thereof from the fluid in a gaseous state; and
A step 4 for further separating impurities in a liquid state or a solid state or a mixed state thereof from the fluid in a gaseous state after the step 3 by using an adsorption type filter;
Is a method for separating and recovering a supercritical fluid containing

In one embodiment of the method for separating and recovering a supercritical fluid according to the present invention, in step 3, impurities are filtered while the fluid moves upward in the filter and is discharged from the upper part of the filter. The impurities trapped in the filter and trapped in the filter move downward in the filter by gravity and are discharged from the lower part of the filter.

In another embodiment of the method for separating and recovering a supercritical fluid according to the present invention, a non-adsorption type filter having a second opening smaller than the first opening is used between step 3 and step 4. In addition, the method further includes a step 3 ′ of further separating impurities in a liquid state, a solid state, or a mixed state thereof from the fluid in a gaseous state after the step 3.

In another embodiment of the method for separating and recovering a supercritical fluid according to the present invention, in step 3 ′, the fluid moves in the filter in the horizontal direction or upward, so that the side portion of the filter. Alternatively, the impurities are captured by the filter before being discharged from the top, and the impurities captured by the filter move downward in the filter by gravity and are discharged from the bottom of the filter.

In yet another embodiment of the method for separating and recovering a supercritical fluid according to the present invention, the non-adsorption filter is made of metal, and the adsorption filter is made of chemical fiber, natural fiber or synthetic resin porous membrane. is there.

In yet another embodiment of the method for separating and recovering a supercritical fluid according to the present invention, 90 to 98% of impurities are removed in step 3.

In still another embodiment of the method for separating and recovering a supercritical fluid according to the present invention, the steps 2 to 4 are under a pressure of atmospheric pressure to 7.38 MPa, and the fluid is kept in a gaseous state. Implemented in the state.

In yet another embodiment of the method for separating and recovering a supercritical fluid according to the present invention, step 2 is performed by reducing the fluid temperature by reducing the pressure of the fluid and generating vaporization cold heat.

In yet another embodiment of the method for separating and recovering a supercritical fluid according to the present invention, the supercritical fluid is supercritical carbon dioxide.

In yet another embodiment of the method for separating and recovering a supercritical fluid according to the present invention, the supercritical fluid containing impurities is discharged from the supercritical dyeing apparatus, and the impurities include a dye.

In another aspect of the present invention,
A pressure reducing valve for changing the supercritical fluid containing impurities into a gaseous state;
A first separation having a non-adsorption type filter having a first opening for separating impurities in a liquid state, a solid state or a mixed state thereof from the fluid in a gas state, which is installed after the pressure reducing valve. A tank,
A second separation tank installed after the non-adsorptive filter and having an adsorption filter for further separating impurities in a liquid state, a solid state or a mixed state thereof from the fluid in a gaseous state;
Is a supercritical fluid separation and recovery device.

In one embodiment of the supercritical fluid separation and recovery apparatus according to the present invention, the non-adsorption filter has a structure in which liquid is discharged from the bottom and gas is discharged from the side or top.

In another embodiment of the supercritical fluid separation and recovery device according to the present invention, the first separation tank (201) is for temporarily storing the liquid discharged from the non-adsorption filter (205). The volume is at the bottom of the filter.

In still another embodiment of the supercritical fluid separation and recovery apparatus according to the present invention, the supercritical fluid separation and recovery apparatus is installed between the first separation tank (201) and the second separation tank (203), and the first separation tank ( A third non-adsorptive filter (209) having a second opening smaller than the first opening for further separating liquid state impurities from the fluid in the gaseous state discharged from 201). The separation tank (202) is further provided.

In still another embodiment of the supercritical fluid separation and recovery apparatus according to the present invention, the non-adsorption filter (205, 209, 222) is made of metal, and the adsorption filter (216) is made of chemical fiber, natural. It is made of a fiber or a synthetic resin porous membrane.

In yet another embodiment of the supercritical fluid separation and recovery apparatus according to the present invention, the supercritical fluid is supercritical carbon dioxide.

In yet another embodiment of the supercritical fluid separation and recovery device according to the present invention, the supercritical fluid containing impurities is discharged from the supercritical dyeing device, and the impurities include a dye.

It is the schematic which shows 1st embodiment of the supercritical dyeing | staining system provided with the separation-and-recovery apparatus of the supercritical fluid which concerns on this invention. It is the schematic which shows one Embodiment of the three-stage-type separation tank which concerns on this invention. It is the schematic which shows an example of the separation tank provided with the non-adsorptive filter applicable to this invention. It is the schematic which shows 2nd embodiment of the supercritical dyeing | staining system provided with the separation-and-recovery apparatus of the supercritical fluid which concerns on this invention. It is the schematic of the supercritical dyeing | staining system described in the patent 3954103 gazette (patent document 1). It is a phase diagram of carbon dioxide.

<1. Supercritical fluid separation and recovery method>
In one embodiment of the supercritical fluid separation and recovery method according to the present invention,
Preparing a supercritical fluid containing impurities;
Step 2 of changing the fluid to a gaseous state;
Step 3 of separating impurities in a liquid state or a solid state, or a mixed state thereof from the fluid in a gaseous state using a non-adsorptive filter having a first opening;
Step 4 for further separating impurities in a liquid state or a solid state, or a mixed state thereof from the fluid in a gas state after Step 3 using an adsorption type filter;
including.

(Process 1)
In step 1, a supercritical fluid containing impurities is prepared. As a substance forming a supercritical fluid, a gaseous substance is suitable at normal temperature and normal pressure (eg, 20 ° C., 1 atm), for example, alkane (especially ethane, propane, pentane), ammonia, carbon dioxide, carbon monoxide. , And dinitrogen oxide, but carbon dioxide is preferably used because of its low critical temperature and safety in handling. These substances usually function as a medium for performing supercritical processing. Supercritical fluids containing impurities are produced by various supercritical processes. Examples include supercritical dyeing, supercritical cleaning, supercritical drying, supercritical extraction, and polymer molding using supercritical. For this reason, the impurities associated with the supercritical fluid vary depending on the content of the supercritical treatment.For example, in the case of supercritical dyeing, the waste fibers mixed with the supercritical fluid from the object to be treated by dyes or supercritical dyeing. In addition, impurities such as adhering dust, water, and oil are included as impurities, and the main components in the liquid state of the impurities described in the present invention include water and oil.
Hereinafter, for example, the above-mentioned “impurities in a liquid state, a solid state, or a mixed state thereof” may be simply referred to as “impurities”.

(Process 2)
In step 2, the supercritical fluid is changed to a gaseous state. At this time, if the temperature and pressure conditions are such that at least a part of the impurities are in a liquid state, the liquid state impurities do not dissolve in the gas, so that in step 3, the impurities can be easily gas-liquid separated from the fluid. . The method for changing the supercritical fluid into a gaseous state is not particularly limited, but a method of reducing the pressure is simple and preferable. No special cooling device is required, and a pressure reducing valve is sufficient. Since evaporative heat is generated when the supercritical fluid changes to a gaseous state, the temperature of the fluid naturally decreases. As the temperature of the fluid decreases, the saturation amount of gaseous impurities also decreases and liquid impurities increase, so that the advantage of increasing the separation efficiency can also be obtained. Considering the separation efficiency from impurities, it is preferable to set the temperature and pressure conditions so that the supercritical fluid is in a gaseous state. This is because, when the supercritical fluid changes to a liquid state, the recovery efficiency of the substance that forms the supercritical fluid in step 3 decreases.

Between step 1 and step 2, in order to prevent the temperature of the supercritical fluid from unintentionally occurring and preventing the supercritical fluid from freezing in the pipe or clogging the pipe during transportation. Furthermore, it is preferable to heat as necessary to maintain the supercritical state. The heating method is not particularly limited, but a resistance heating device, an induction heating device, a dielectric heating device, a microwave heating device, a combustion heating device, or the like may be appropriately selected.

(Process 3)
In step 3, impurities in a liquid state are separated from the fluid in a gas state using a non-adsorption filter having a first opening. Here, the non-adsorptive filter refers to a filter made of a material that does not adsorb the trapped liquid impurities on the surface, and if defined in detail, the impurities are temporarily collected by collision with the filter material surface. A filter that cannot stay long due to its material and smooth shape. Examples of materials that do not absorb impurities on the surface include stainless steel, iron, copper, silver, zinc, nickel, chromium, aluminum, Hastelloy, Inconel and other inorganic filters such as glass and ceramics. Stainless steel that is tough, does not rust, has heat resistance, and is affordable is preferable. Examples of the shape of the filter in the step 3 include a demister type, a mesh type, a pleat type, a bag type, a candle type, and a laminated type, and the demister type is preferable because it has a high efficiency of collecting a large amount of large impurities. If a non-adsorptive filter is used, liquid impurities will naturally fall off the filter by gravity, so there is no need to replace the filter and little maintenance is required. Even if dirt is generated, the performance can be maintained by washing.

大 Most liquid impurities can be separated by using only non-adsorptive filters. For example, the opening of the filter can be set so that 90 to 98%, typically 92 to 96%, of impurities can be removed. It is also possible to arrange the filters in series or in parallel depending on the throughput. If the separation efficiency of impurities in step 3 is set too low, the burden on the subsequent adsorption filter becomes heavy and the replacement frequency increases. On the other hand, if the separation efficiency of impurities in step 3 is set too high, the apparatus becomes larger, the separation speed becomes slow, clogging tends to occur, and the replacement frequency increases. In addition, the price of the filter itself increases. Furthermore, there is a limit to the separation efficiency. Therefore, it is desirable to set the opening of the non-adsorption filter in step 3 with the separation efficiency in the above-mentioned range as a guide.

If the aperture of the filter in step 3 is too small, the transmission efficiency is poor and the separation speed is slow. On the other hand, if it is too large, almost no unwanted matter is collected and the filter passes through. The opening size is 0.5 μm to 270 μm on average, and more preferably 1 μm to 20 μm on average. The size of the mesh is defined as the diameter of the smallest circle that can pass through each mesh when the filter mesh is observed with SEM, and the average value of any 100 or more meshes is defined as the mesh size. The average value of

In order to improve the separation efficiency of impurities, it is desirable to use a filter having a structure in which liquid is discharged from the bottom and gas is discharged from the side or top. When a filter having such a structure is used, impurities are trapped in the filter while the fluid moves horizontally or upward in the filter and is discharged from the side or top of the filter. The impurities trapped in the filter move downward in the filter by gravity and are discharged from the bottom of the filter. Since the moving direction of the impurities and the moving direction of the fluid are different, the separation between the two is promoted.

(Process 4)
In step 4, impurities are further separated from the fluid in the gaseous state after step 3 using an adsorption filter. In the present invention, the adsorption filter refers to a filter made of a material that adsorbs trapped liquid impurities on the surface. If defined in more detail, the van der Waals strong due to the material and the porous or fine complex shape. It is a filter that has power, traps impurities, collects them, and is difficult to suck and release. Examples of the filter made of a material that adsorbs impurities on the surface include chemical fiber, natural fiber, and synthetic resin porous membrane. Examples of the chemical fiber include resin, particularly PET, PP (polypropylene), Nylon, and urethane. Filters made of synthetic fibers made of synthetic resin such as acrylic, acetate, rayon, and natural fibers include, for example, filters made of plant fibers and animal fibers such as cotton, hemp, silk, wool, paper, etc. Examples of the resin porous membrane include porous membranes of synthetic resins such as PE (polyethylene), PP (polypropylene), PU (polyurethane), EVA (polyethylene vinyl acetate), PTFE (polytetrafluoroethylene) and the like. Nonwoven fabrics or woven fabrics using PP are preferred for reasons such as processability, durability and economy. Examples of the shape of the filter in step 4 include a demister type, a mesh type, a pleat type, a bag type, a candle type, a laminated type, and the like. A demister type is preferable because it has a high efficiency for collecting a large amount of impurities. Although the adsorption type filter shows very good separation efficiency, the liquid containing the trapped impurities is adsorbed in the filter, so that the filter needs to be replaced when the adsorption capacity of the filter is exceeded. Therefore, it is preferable to reduce the replacement frequency while maintaining the performance of the adsorption filter used in step 4 in order to increase the practicality of the supercritical fluid separation and recovery method according to the present invention. It is also possible to arrange the filters in series or in parallel depending on the throughput.

As described above, in the present invention, most of the impurities are separated from the fluid by the non-adsorptive filter in step 3. In step 4, since the remaining trace amount of impurities only needs to be separated, the load on the adsorption filter can be very small, and the replacement frequency is greatly reduced. Although only a few percent of the total impurities are separated in step 4, it is an important step for recovering and reusing a high purity fluid. After step 4, it is preferable that 99% or more of impurities in the fluid are removed, more preferably 99.5% or more, and even more preferably 99.9% or more. .

(Process 3 ')
In order to reduce the load on the adsorptive filter in step 4, a non-adsorbing filter having an opening smaller than the first opening is used between step 3 and step 4 to change the gas state after step 3 It is possible to further perform step 3 ′ of further separating impurities from the fluid. Because non-adsorptive filters are used, maintenance is high. By performing step 3 ′, the impurity separation efficiency can be increased by 2 to 6%, typically 3 to 5%. Therefore, the impurities transferred to the subsequent step 4 can be 2% or less, preferably 1% or less of the total impurities.

By making the opening of the non-adsorptive filter used in step 3 'smaller than that of the non-adsorptive filter used in step 3, fine droplets that cannot be separated in step 3 can be removed. If the aperture of the filter in step 3 ′ is too small, the transmission efficiency is poor and the separation speed is slow. On the other hand, if it is too large, many unnecessary substances pass through the filter. The average size is 0.1 μm to 10 μm on average, and more preferably 0.1 μm to 1 μm on average. The definition of the opening size is as described above.

The material and shape of the non-adsorptive filter used in step 3 ′ may be the same as in step 3,
In view of the optimum strength, durability and economy, the material is stainless steel, and the shape is preferably a pleated type having a wide filtration area per unit volume from the relationship between the filter volume and the filtration area. In order to increase the separation efficiency of impurities, it is desirable to use a filter having a structure in which the liquid is discharged from the bottom and the gas is discharged from the side or top, as in step 3.

(Other)
The fluid from which impurities are separated after exiting Step 4 can be stored in a gaseous state, but in view of reuse as a supercritical fluid and storage space, the fluid is liquefied and the volume is reduced. It is desirable to save it with. Further, considering that the fluid subjected to the supercritical treatment is repeatedly circulated and used, it is desirable to carry out the steps 2 to 4 while maintaining a high pressure in order to suppress the energy consumption required for the pressure increase as much as possible. For this reason, steps 2 to 4 are performed in a pressure-resistant container, when the fluid is kept in a gas state and the impurities are kept in a liquid state at a high pressure, for example, when carbon dioxide is used as a supercritical fluid, FIG. The pressure and temperature are set within the range shown in (3) of the carbon dioxide phase diagram shown. That is, it refers to a temperature that is not higher than the supercritical pressure, not higher than 7.38 MPa, preferably not lower than atmospheric pressure, and is in a gaseous state.

<2. Supercritical fluid separation and recovery device>
An embodiment of a supercritical fluid separation and recovery apparatus for realizing the above-described supercritical fluid separation and recovery method according to the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 shows a schematic diagram of a first embodiment of a supercritical dyeing system using carbon dioxide as a dyeing medium, equipped with a supercritical fluid separation and recovery apparatus 100 according to the present invention. The supercritical dyeing system according to this embodiment includes a cooler 101, a supply pump 102, a preheater 103, a supply opening / closing valve 104, an autoclave 105, a circulation pump 107, a pressure sensor 111, a pressure reducing valve 115, a separation tank 116, and a carbon dioxide storage tank. 119.

The liquefied carbon dioxide is stored in the carbon dioxide storage tank 119, and after being pressurized by the supply pump 102 until it changes to a supercritical state, it is sent to the autoclave 105 through the supply opening / closing valve 104. Although not shown, a fiber product is held in the autoclave 105, and a dye dissolved in supercritical carbon dioxide is supplied to the fiber product to be dyed. When dyeing textiles using supercritical carbon dioxide as a dyeing medium, disperse dyes and oil-soluble dyes are preferably used as dyes.

When the supply of supercritical carbon dioxide is started, the circulation pump 107 is operated to circulate the supplied supercritical carbon dioxide through the autoclave 105 in the direction of arrow A in the figure. As a result, the supercritical carbon dioxide flows out from the outlet of the autoclave 105 and is then reintroduced into the inlet of the autoclave 105 through the circulation path. By circulating and using supercritical carbon dioxide, it is possible to uniformly dye textile products, and to suppress the consumption of carbon dioxide, thereby reducing costs.

Also, the pressure sensor 111 measures the pressure in the autoclave 105 and controls the operation of the supply pump 102. Thereby, the pressure in the autoclave 105 is adjusted and held at a predetermined set pressure for performing the dyeing process.

When the dyeing process is completed, the circulation pump 107 is stopped, and the supercritical carbon dioxide in which the dye is dissolved is directed to the pressure reducing valve 115. The pressure reducing valve 115 controls the discharge amount of carbon dioxide and vaporizes supercritical carbon dioxide that has passed through the pressure reducing valve 115. Impurities such as dyes are gas-liquid separated from carbon dioxide in the separation tank 116. FIG. 2 is a schematic diagram showing an example of the structure of the separation tank 116. A flow chart showing the flow of carbon dioxide and impurities in the lower stage, and an arrangement of filters in each separation tank in the separation tank 116 in the upper stage. A schematic cross-sectional view for the purpose is drawn. As shown in FIG. 2, the separation tank 116 has a three-stage structure including a first separation tank 201, a second separation tank 203, and a third separation tank 202. The third separation tank 202 can be omitted, but it is desirable to install it from the viewpoint of reducing the burden on the second separation tank 203 and improving the maintainability.

The first separation tank 201 is installed after the pressure reducing valve 115 and has a non-adsorption filter 205 having a first opening for separating impurities 206 from carbon dioxide in a gaseous state. Carbon dioxide flowing from the inlet 204 of the substantially cylindrical first separation tank 201 moves downward through a space provided between the inner wall of the first separation tank 201 and the outer wall of the cylindrical filter 205. After that, it reverses and enters the filter through the opening at the bottom of the filter. Carbon dioxide contains impurities 206 in the form of fine droplets, and the impurities are captured by the non-adsorbing filter 205 while the carbon dioxide passes upward through the filter 205 extending in the vertical direction. Separated from.

Impurities trapped in the non-adsorbing filter 205 move downward in the filter 205 due to gravity, and are finally stored in the space at the bottom of the first separation tank 201 from the opening at the bottom of the filter 205, and finally Is discharged from the liquid outlet 207. What is separated in the first separation tank 201 is an impurity having a relatively large droplet diameter and solid particle diameter, and most of the liquid impurity is separated here.

The carbon dioxide discharged from the outlet 208 through the opening at the top of the filter 205 goes to the third separation tank 202. The third separation tank 202 has a non-adsorption filter 209 for further separating impurities 210 such as a dye in a liquid state from carbon dioxide in a gas state. The opening of the filter in the third separation tank is set smaller than the opening of the filter in the first separation tank in order to increase the separation efficiency.

The carbon dioxide flowing from the inlet 211 of the substantially cylindrical third separation tank 202 passes downward through the space between the inner wall of the third separation tank 202 and the concentric inner pipe provided inside thereof. Moving. The carbon dioxide emitted from the opening provided at the bottom of the third separation tank 202 is reversed and is placed in a plurality of cylindrical filters 209 that are evenly arranged in the circumferential direction near the center of the third separation tank 202. Enter from the bottom and sides of the filter. The carbon dioxide contains finer droplets and fine solid impurities 210 that could not be removed by the first separation tank 201, and the impurities are generated while carbon dioxide passes upward through the filter 209. It is captured by the non-adsorbing filter 209 and separated from carbon dioxide.

Impurities trapped in the non-adsorbing filter 209 move downward in the filter 209 due to gravity, and are eventually stored in the space at the bottom of the third separation tank 202 from the opening at the bottom of the filter 209, and finally Is discharged from the liquid outlet 212. What is separated in the third separation tank 202 is an impurity having a relatively small droplet diameter and solid particle diameter, and the amount of impurities recovered here is much smaller than that in the first separation tank. However, the third separation tank 202 plays an important role from the viewpoint of reducing the filter replacement frequency of the second separation tank 203.

In this embodiment, in order to explain the variation of the structure of the separation tank, the structure of the third separation tank 202 is changed to that of the first separation tank 201, but the structure is particularly different except for the opening of the filter. There is no need to do this, and both may have the same structure. Each separation tank may have a different structure. FIG. 3 shows still another example of a separation tank provided with a non-adsorption filter.

Carbon dioxide flows from the inlet 221 of the substantially cylindrical separation tank 220 and moves downward through the space between the inner wall of the separation tank 220 and the concentric inner pipe provided inside thereof. After the carbon dioxide exits from the opening provided at the bottom of the separation tank 220, it is reversed and enters the cylindrical non-adsorption filter 222 installed near the center of the separation tank 220 from the bottom and outside of the filter. The fine droplet-like or fine solid-state impurities 223 contained in the carbon dioxide are captured by the non-adsorption filter 222 until the carbon dioxide passes through the filter 222 and emerges from the inner side of the filter. Separated from carbon dioxide.

The impurities 223 captured by the non-adsorbing filter 222 move downward in the filter 222 due to gravity, eventually come out of the bottom of the filter 222 and fall due to gravity, and are temporarily stored in the bottom of the separation tank 220. Is discharged from the liquid outlet 224. What is necessary is just to set suitably the magnitude | size of the opening of the filter 222 according to whether it uses as a 1st separation tank or a 2nd separation tank.

Now, referring to the third separation tank 202 in FIG. 2 again, the carbon dioxide discharged from the outlet 213 through the opening at the top of the filter 209 goes to the second separation tank 203. The second separation tank 203 has an adsorption filter 216 for further separating impurities 215 such as a dye in a liquid state from carbon dioxide in a gas state. Carbon dioxide flowing from the inlet 214 of the substantially cylindrical second separation tank 203 passes downward through the space between the inner wall of the second separation tank 203 and the concentric inner pipe provided inside thereof. Moving. The carbon dioxide emitted from the opening provided at the bottom of the second separation tank 203 is reversed and placed in a plurality of cylindrical filters 216 arranged in the circumferential direction evenly in the vicinity of the center of the second separation tank 203. Enter from the top and sides of the filter. The carbon dioxide contains even finer droplets and fine solid impurities 215 that could not be removed by the third separation tank 202, while carbon dioxide passes downward through the filter 216. Impurities are captured by the adsorption filter 216 and separated from carbon dioxide. The cleaned carbon dioxide after passing through the filter 216 is discharged from the outlet 217. The carbon dioxide can be reused for the supercritical dyeing process.

Although the adsorption type filter 216 has high impurity separation efficiency, the impurity 215 is adsorbed and fixed to the filter 216. Therefore, when the adsorption capacity of the filter 216 is exceeded, the separation efficiency is extremely lowered. Therefore, it is necessary to replace the filter regularly. In the present invention, since most impurities can be separated and removed in the previous stage, the role in the second separation tank 203 is to separate, for example, only about 1% of impurities. For this reason, it is possible to reduce the maintenance frequency to about 1/100 compared to the case where a separation tank using a non-adsorption filter is not installed in the previous stage.

(Second embodiment)
FIG. 4 shows a schematic diagram of a second embodiment of a supercritical dyeing system using carbon dioxide as a dyeing medium equipped with the supercritical fluid separation and recovery apparatus 300 according to the present invention. The supercritical dyeing system according to this embodiment includes a supply pump 102, a supply on-off valve 104, an autoclave 105, a circulation pump 107, a pressure sensor 111, a heater 114, a pressure reducing valve 115, a separation tank 116, a compressor 117, and an after cooler 118. The carbon dioxide storage tank 119 is provided.

The carbon dioxide storage tank 119 stores liquefied carbon dioxide, and is pressurized by the supply pump 102 until it changes to a supercritical state, and then sent to the autoclave 105 via the supply opening / closing valve 104 and the preheater 103. . By heating supercritical carbon dioxide with the preheater 103, the supercritical state can be stably maintained. Although not shown, a fiber product is held in the autoclave 105, and a dye dissolved in supercritical carbon dioxide is supplied to the fiber product to be dyed.

Since the operations of the circulation pump 107 and the pressure sensor 111 during the dyeing process are as described in the first embodiment, they are omitted.

When the dyeing process is completed, the circulation pump 107 is stopped, and the supercritical carbon dioxide in which the dye is dissolved passes through the heater 114 and the pressure reducing valve 115 and then flows into the separation tank 116 in a gaseous state. The heater 114 plays a role in preventing the temperature of the supercritical fluid from unintentionally occurring and freezing the supercritical carbon dioxide in the pipe or blocking the pipe during transportation. In the separation tank 116, as described above, impurities such as dyes are separated from carbon dioxide.

The gaseous carbon dioxide cleaned through the separation tank 116 is pressurized by the compressor 117 for reuse and further liquefied by being cooled by the aftercooler 118. The liquefied carbon dioxide is returned to the carbon dioxide storage tank 119 to be ready for repeated use.

100 Supercritical fluid separation and recovery device 101 Cooler 102 Supply pump 103 Preheater 104 Supply on-off valve 105 Autoclave 107 Circulation pump 111 Pressure sensor 114 Heater 115 Pressure reducing valve 116 Separator 117 Compressor 118 After cooler 119 Carbon dioxide storage tank 201 One separation tank 202 Third separation tank 203 Second separation tank 204 First separation tank inlet 205 Non-adsorption filter 206 Impurity 207 Liquid outlet 208 First separation tank outlet 209 Non-adsorption filter 210 Impurity 211 Third separation tank inlet 212 Liquid outlet 213 Third separation tank outlet 214 Second separation tank inlet 215 Impurity 216 Adsorption filter 217 Second separation tank outlet 220 Separation tank 221 Separation tank inlet 22 unadsorbed-type filter 223 impurity 224 liquid outlet 225 separation tank outlet 300 separation and recovery device of the supercritical fluid

Claims

Preparing a supercritical fluid containing impurities;
Step 2 of changing the fluid to a gaseous state;
Using a non-adsorbing filter (205) having a first aperture to separate impurities in a liquid state, a solid state or a mixed state thereof from the fluid in a gaseous state; and
A step 4 for further separating impurities in a liquid state or a solid state or a mixed state thereof from the fluid in a gaseous state after the step 3 by using an adsorption filter (216);
A method for separating and recovering a supercritical fluid including
In step 3, impurities are trapped in the filter (205) until the fluid moves upward in the filter (205) and discharged from the upper part of the filter (205), and the filter (205) The method for separating and recovering a supercritical fluid according to claim 1, wherein the trapped impurities move downward in the filter (205) by gravity and are discharged from the lower part of the filter (205).
Between step 3 and step 4, using a non-adsorption type filter (209) having a second opening smaller than the first opening, the fluid in the gas state after step 3 is in a liquid state or solid The method for separating and recovering a supercritical fluid according to claim 1, further comprising a step 3 ′ of further separating impurities in a state or a mixed state thereof.
In step 3 ′, the impurities move in the filter (209) in the horizontal direction or upwards until impurities are discharged from the side or top of the filter (209). 4. The method for separating and recovering a supercritical fluid according to claim 3, wherein the impurities trapped by the filter and captured by the filter (209) move downward in the filter (209) by gravity and are discharged from the bottom of the filter (209). .
The non-adsorption type filter (205, 209, 222) is made of metal, and the adsorption type filter (216) is made of chemical fiber, natural fiber, or synthetic resin porous membrane. 2. A method for separating and recovering a supercritical fluid according to 1.
The method for separating and recovering a supercritical fluid according to any one of claims 1 to 5, wherein 90 to 98% of impurities are removed in step 3.
The supercritical fluid according to any one of claims 1 to 6, wherein steps 2 to 4 are performed under a pressure of atmospheric pressure to 7.38 MPa and the fluid is maintained in a gaseous state. Separation and recovery method.
The method for separating and recovering a supercritical fluid according to any one of claims 1 to 7, wherein the step 2 is performed by reducing the fluid pressure and generating vaporization cold heat to lower the fluid temperature.
The method for separating and recovering a supercritical fluid according to any one of claims 1 to 8, wherein the supercritical fluid is supercritical carbon dioxide.
The method for separating and recovering a supercritical fluid according to any one of claims 1 to 9, wherein the supercritical fluid containing impurities is discharged from the supercritical dyeing apparatus, and the impurities include a dye.
A pressure reducing valve (115) for changing the supercritical fluid containing impurities into a gaseous state;
Non-adsorptive filter (205) installed at the rear stage of the pressure reducing valve (115) and having a first opening for separating impurities in a liquid state, a solid state or a mixed state thereof from the fluid in a gaseous state A first separation tank (201) having
Second separation having an adsorptive filter (216) installed after the non-adsorptive filter (205) and further separating impurities in a liquid state, a solid state or a mixed state thereof from the fluid in a gaseous state A tank (203);
A supercritical fluid separation and recovery device (100, 300).
The supercritical fluid separation and recovery device according to claim 11, wherein the non-adsorbing filter (205) has a structure in which a liquid is discharged from a bottom portion and a gas is discharged from a side portion or a top portion.
The supercritical fluid according to claim 11 or 12, wherein the first separation tank (201) has a volume for temporarily storing the liquid discharged from the non-adsorptive filter (205) at a lower part of the filter. Separation and recovery device.
Impurities are further separated from the fluid in the gaseous state, which is installed between the first separation tank (201) and the second separation tank (203) and discharged from the first separation tank (201). The third separation tank (202) further comprising a non-adsorption type filter (209) having a second opening smaller than the first opening for the purpose. The supercritical fluid separation and recovery device described.
The non-adsorption filter (205, 209, 222) is made of metal, and the adsorption filter (216) is made of a chemical fiber, a natural fiber, or a synthetic resin porous membrane. The supercritical fluid separation and recovery device described in 1.
The supercritical fluid separation and recovery device according to any one of claims 11 to 15, wherein the supercritical fluid is supercritical carbon dioxide.
The supercritical fluid separation and recovery device according to any one of claims 11 to 16, wherein the supercritical fluid containing impurities is discharged from the supercritical dyeing device, and the impurities include a dye.